The objective of this study is to examine certain clinically- significant aspects of the relationship between the nutritional state of women and the level of pituitary gonadotropic function. This will be accomplished by determining by radio-immunoassay the levels of serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH), and making certain auxiliary measurements in two groups of subjects: (1) slightly obese post-menopausal women, and (2) undernourished women of reproductive age with secondary amenorrhea attributable to injudicious dieting. The post-menopausal women will be studied on a metabolic ward during a 10-day period of total starvation intended to exaggerate the effects of a "crash" diet. The undernourished women will be followed on an outpatient basis during a period of controlled re-feeding designed to increase their weight to a level which is normal for their age and height.